The process of cold forming metals is well known in the art. Typically a deformable or malleable metal is deformed at room temperature through a series of compression and/or expansion steps. Cold forming has been used to form various articles including automotive items such as spark plug housings and battery terminals. Typically, spark plug housings are made of steel alloys and other articles, including battery terminals, are made of softer metals such as lead or lead alloys. While cast battery terminals have been used satisfactorily, cold formed battery terminals may be preferable since the working of the metals during the cold forming process appears to remove air pockets. The result is a more dense terminal that hinders electrolyte from escaping through the terminal. Although lead can be cold formed quite readily the leak-proof sealing of lead terminals to battery containers after the terminal has been formed is difficult since the battery terminal also needs to have a leak-proof seal between the terminal and the battery wall. Sealants have now been developed that enable battery manufactures to seal cold formed battery terminals to the battery container in a leakproof relationship.
One of the first cold formed battery terminals that was commercially available is shown in the Gould Inc. drawings dated 1974. The product was made and sold by applicant's assignee Water Gremlin Company to Gould Inc. in 1974.
Another commercially available battery terminal made and sold by applicant's assignee Water Gremlin Company is shown in the U.S. Pat. No. 4,662,205 which shows the cold forming of a finished battery terminal for a starved lead acid battery used as back up power source for an emergency lighting system. The U.S. Pat. No. 4,662,205 shows a machine for cold casting battery electrodes through use of end punches. In this process, a slug is cut off by machine and automatically fed into a chamber where the opposite ends of the slug are compressed between opposing punches to form a battery terminal. The U.S. Pat. No. 4,776,197 shows a method for forming a semi-finished battery terminal through a cold-forging process where the cylindrical slug is also compressed from opposite ends and subsequently finished to remove the unfinished ends of the battery terminal slug.
The present invention comprises an improved battery terminal that has high torque resistance to help prevent the terminal from coming loose from the container. In addition the present invention provides a process for cold forming a lead slug into a finished battery terminal that can be directly inserted into a battery container.